Shielded high voltage connector

ABSTRACT

A shielded electrical connector for a high voltage cable having a section of the cable insulation removed to expose a conductor, the connector including an electrically insulating member surrounding the cable insulation and conductor, and an electrically conductive shield surrounding said insulating member. The conductive shield is formed from a layer of electrically conductive material and a metallic mesh, the shield being bonded to the outer surface of the insulating member. A disconnect assembly can be provided for selectively connecting and disconnecting the shield to the cable.

gh voltage cable 11 removed to exg an electrig the cable insulatricallyconductive yer of electrically c mesh, the shield the insulating Aug.14, 1973.

3,390,331 6/1968 Brown et Primary Examiner-Marvin A. Champion AssistantExaminer-Robert A. Hafe Attorney-Ronald E. Barry et al.

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United States Patent [1 1 Link [ SHIELDED HIGH VOLTAGE CONNECTOR [75]Inventor: Edwin A. Link, Waukesha, Wis. [73] Assignee: RTE Corporation,Waukesha, Wis.

[22] Filed: June 30, 1971 [21] App1.No.: 158,159

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UNITED STATES PATENTS 3,376,541 I 4/1968 2,522,072 9/1950 Tiemey....3,617,987 11/1971 3,585,568 6/1971 l SHIELDED HIGH VOLTAGE CONNECTORBACKGROUND OF THE INVENTION An electrical connector or terminator of thetype contemplated herein is shown in US. Pat. No. 3,376,541 entitledSafe Break Terminator. This connector includes a plug assembly having aninsulating member surrounding the cable and a conductive shield on theouter surface of the insulating member, either coated thereon or formedas a separate layer which is then bonded to the insulator. Theconductive shield is provided to protect the lineman from high voltageswhich may be present in the conductor. However, in the event of a fault,the high current present on the insulator tends to be grounded by thelineman rather than through the shield. This is due to the highresistance of the electrically conductive shield.

SUMMARY OF THE PRESENT INVENTION The electrical connector of the presentinvention includes an insulating member for the cable and a lowresistance electrically conductive shield on the outer surface of theinsulator. The conductive shield includes a metallic mesh to provide alow resistance path from the external conductive shield to the cablesheath. The shield can be connected to the semi-conductive sheath of thecable by a disconnectable type assembly provided on the conductiveshield. The conductive shield can also be permanently connected to thesheath by an interference fit at the sheath end of the connector. If theshield is insulated from the grounded sheath, the shield can then beused as a means for detecting the presence of a voltage on the cable.This is due to the capacitive relationship of the conductive shield tothe conductor in the cable.

Other objects and advantages of this invention will become apparent fromthe. following description when read in connection with the accompanyingdrawings.

THE DRAWINGS FIG. 1 is a side elevation view in section showing theconnector of the present invention; i

FIG. 2 is an enlarged view of a portion of the stress cone of theconnector showing the conductive shield permanently connected to thecable sheath;

FIG. 3is a view of a portion of the connector showing the connectorshield connection to the cable concentric neutral; and

FIG. 4 is a view of an alternate form of disconnect assembly fordisconnecting the cable sheath and concentric neutral to the conductiveshield of the connector.

DESCRIPTION OF THE INVENTION The connector of the present invention isshown and described herein as an elbow connector for terminating a highvoltage cable 12. It should be recognized, however, that the connector10 can also be used to form a splice in a high voltage cable byproviding similar connections to the cable sheath at each end of theconnector as described hereinafter.

Referring to FIGS. 1 and 3 of the drawings, the electrical connector 10of the present invention is shown as a terminator for a high voltagecable 12 of the type having a cable sheath 14 including a concentricneutral formed of a number of electrically conductive strands 15, acable insulation 16, and a conductor 18. The cable 12 is normallyprepared for termination by unwinding the strands 15 of the concentricneutral from the end of the cable and stripping the semi-conductivesheath 14 from the cable 12 to expose a portion of the cable insulation16. A portion of the cable insulation 16 is then removed from the end ofthe cable 12 to expose a portion of the conductor 18.

As is generally well known, cable termination is made by securing orcrimping a conductive member to the conductor 18 and inserting the endof the cable 12 with the conductive member 20 attached into theconnector 10. The conductive member 20 includes a threaded opening 21and is retained in the connector 10 by means of a conductive contact 22which has a threaded section 24. The threaded section 24 is screwed intothe threaded opening 21 provided in the conductive member 20. Theconductive contact 22 extends outwardly into a recess 25 provided in theconnector 10.

The electrical connector 10 is mounted on a receptacle 26 which has anouter surface 29 corresponding to the inner surface of the recess 25'and a conductive sleeve 28 positioned to receive the tubular contact 22.The receptacle 26 can be any form of high voltage contact such as usedon a transformer, cable splice, etc. or another high voltage cable ifthe connector is used to form a splice.

The connector 10 generally includes an insulating member 30 and anelectrically conductive shield 32. An electrically conductive insert orlining can be pro vided on the inner surface of the insulator toeliminate electrical stress on the void around the conductive member 20and contact 22.

The insulating member 30 is generally molded from a dielectric materialand includes the tapered recess 25 and a cable passage or opening 36.The insulating member 30 is shielded by means of the electricallyconductive shield 32 which includes a coating or layer 38 ofelectrically conductive material secured to the outer surface of theinsulating member 30. The coating or layer 38 is insulated from thecable 12 by means of small sections 40 and 42 of the insulating memberwhich extend beyond the end of the shield 32.

. The insulating member 30, the shield 32, and the lining 34 are allformed of an elastomer or rubber. A conductive material such aslampblack, graphite or carbon black is combined with the elastomer orrubber used for the shield 32 and lining 34. The member 30, shield 32and lining 34 are molded to the desired shape as is generally understoodin the art.

In accordance with the invention, means are provided in the connector 10to provide a low resistance current path to ground. Such means is in theform of a metallic material which is shown embedded in the conductivelayer 38. It should be noted, however, that the metallic material 50 canbe embedded in the outer surface of the insulating member 30 in thespace between the insulating member 30 and the layer of conductiveelastomer 38 or within the layer 38 as shown. The metallic material inthe preferred form shown in the drawing is in the form of a metallicmesh. Metallic material in the form of strands of metal or metallicchips can also be used. A high conductive metal such as copper should beused to provide the low resistance path for any fault currents which mayoccur in the connector.

Means are provided for connecting the shield 32 to the semi-conductivesheath 14 of the cable 12. Such means is in the form of a disconnectassembly 52 which is partially embedded in the shield 32. In thisregard, the assembly 52 includes a sleeve 54 having a threaded opening56 and a flange 58 at the inner end. The flange 58 and a portion of thesleeve 54 are embedded within the conductive layer 38, with the open endof the sleeve 54 extending outward from the outer surface of the shield32. A hot stick type screw 60 having a threaded section 62 is threadedlyreceived in the sleeve 54 and a number of strands of the concentricneutral are connected to the screw 60. In the event of a fault currentoccurring in the conductor 18, the low resistance metallic material willprovide a low resistance path through the assembly 52 and cable sheath14 to ground.

The conductive shield 32 can be permanently connected to the cablesheath by means of an interference fit as shown in FIG. 2. In thisembodiment, the section 40 has been removed from the insulating member30 and the diameter of the opening at the end 31 of the insulatingmember has been made slightly smaller than the diameter of the cablesheath 14. An interference fit is thereby provided which assureselectrical contact between the conductive shield 32 and the cablesheath. The strands of the concentric neutral can be wrapped around theend 31 of the insulating member.

The conductive shield 32 can be used to detect the absence or presenceof a voltage on the cable by disconnecting the conductive shield 32 fromthe cable sheath 14. This is accomplished by means of the disconnectassembly 52. In this regard, on removal of screw 60 and strands 15 fromthe sleeve 54', the conductive shield will be insulated from the cablesheath 14 by the small sections 40 and 42 of the insulating member 30.The layer of conductive material 38 will then provide a capacitivereaction to any voltage present in conductor 18. Contacting theconductive shield 32 with a voltage sensing device will then provide anindication of the absence or presence of voltage on the cable.

In the alternate form of the means for connecting the shield 32 to thesheath 14 in FIG. 4, a disconnect assembly 69 having an electricallyconductive collar 70 and a conductive contact 74 is mounted on the cable12. The collar 70 is formed of an electrically conductive material asdescribed above in connection with conductive layer 38 and includes aconical section 72. The collar 70 is connected to the semi-conductivesheath 14 by means of the electrically conductive contact 74 which isprovided on a metal ring 76 mounted on the collar 70 and is connected tothe strands 15 of the concentric neutral. After cable termination hasbeen completed, the collar 70 is pushed upward into engagement with theconnector 10 with the conical section 72 in engagement with the shield32 on the connector 10. A low resistance connection is then providedfrom the shield 32 through the collar 70'and the connector 74 to thesheath 14. When it is desired to disconnect the conductive shield 32from ground, the conical section 72 is turned back as shown in phantomline in FIG. 4. 1

The elbow connector 10 can be disconnected from the bushing 26 by meansof an eye provided in the conductive shield 32. The eye 80 can bereinforced by providing a metallic insert or plate 82 having an opening84 within the conductive material. The inserts 82 should extend around aportion of the outer surface of the insulating member 30 to anchor theinsert firmly into the conductive material.

RESUME The connector 10 of this invention protects the lineman frompossible electrical shocks due to high currents which may be present onthe connector. This is accomplished by incorporating a metallic materialin the conductive shield of the connector to provide a low resistancecurrent path to ground. The low resistance current path should have aresistance less than the resistance path through the body of a man toassure that high currents will be grounded through the connector. Theincorporation of the metallic mesh in a semiconductive resilient shieldallows the connector to be forced onto a bushing without adverselyaffecting the conductive shield. The conductive shield can also be usedto detect voltage by disconnecting the conductive shield from the cablesheath.

7 Iclaim:

1. A cable connector for a high voltage cable having a cable sheath,said connector comprising,

an electrically insulating member adapted to be mounted on the cable andhaving an interference fit therein,

an electrically conductive shield on the outer surface of saidinsulating member,

said shield being formed from an electrically conductive low resistancemetallic mesh and a layer of electrically conductive high resistanceresilient material,

and electrically conductive means for grounding said shield and metallicmesh to the cable sheath whereby high fault currents present in thecable are grounded through the cable sheath.

I 2. The connector according to claim 1 wherein said metallic materialis embedded in said layer of electrically conductive resilient mesh.

3. The connector according to claim 1 wherein said metallic mesh ismounted in tight engagement with the outer surface of said insulatingmember and said resilient layer completely covers the mesh and the outersurface of said insulating member.

4. The connector according to claim 1 wherein said grounding meanscomprises a conductive disconnect assembly partially embedded in saidshield in direct contact with said mesh and adapted to be connected tothe semi-conductive sheath of the cable.

1. A cable connector for a high voltage cable having a cable sheath,said connector comprising, an electrically insulating member adapted tobe mounted on the cable and having an interference fit therein, anelectrically conductive shield on the outer surface of said insulatingmember, said shield being formed from an electrically conductive lowresistance metallic mesh and a layer of electrically conductive highresistance resilient material, and electrically conductive means forgrounding said shield and metallic mesh to the cable sheath whereby highfault currents present in the cable are grounded through the cablesheath.
 2. The connector according to claim 1 wherein said metallicmaterial is embedded in said layer of electrically conductive resilientmesh.
 3. The connector according to claim 1 wherein said metallic meshis mounted in tight engagement with the outer surface of said insulatingmember and said resilient layer completely covers the mesh and the outersurface of said insulating member.
 4. The connector according to claim 1wherein said grounding means comprises a conductive disconnect assemblypartially embedded in said shield in direct contact with said mesh andadapted to be connected to the semi-conductive sheath of the cable.